A Novel Fluorometric Ultramicro Determination of Serum γ-Glutamyltranspeptidase Activity

Abstract

A simple and highly sensitive rate assay of serum γ-glutamyltranspeptidase activity is described, using a novel fluorogenic substrate, 7-(γ-L-glutamyl)-4-methylcoumarinylamide. The reaction is initiated by adding 20 μl of serum, and fluorescence development in 1 min due to the 7-amino-4-methylcoumarin liberated at 37°C is followed directly on a recorder. A close correlation was found between activities measured by the fluorometric method and by a conventional method using a chromogenic substrate, γ-L-glutamyl-p-nitronanilide.